U.S. Pat. No. 4,629,493 discloses herbicidal compounds of the following formula: wherein A is —CH— or —N—; X is a halogen; n is 0,1, or 2; R1 is hydrogen or a lower alkyl group; and R2 is —OH, among other values. One of these compounds is currently sold commercially for the control of annual and perennial grass weeds in broadleaf crops. This compound has the following formula: 
Corbett et. al., Investigational New Drugs, 16 129-139 (1998) evaluated a series of quinoxaline compounds for activity against solid tumors in mice. The following compound (referred to as XK469) was reported to have broad activity against transplantable mouse tumors. The compound was also reported to have a relatively low potency, and to produce several undesirable side effects, including in vivo toxicity, e.g., paralytic ileus, GI-epithelial damage, marrow toxicity, neuromuscular toxicity and weight loss. There is currently a need for additional antitumor agents.